(function() {
        var m = Math
            , mround = function(r) {
                return r >> 0;
            }
            , vendor = (/webkit/i).test(navigator.appVersion) ? 'webkit' : (/firefox/i).test(navigator.userAgent) ? 'Moz' : 'opera'in window ? 'O' : ''
            ,
            // Browser capabilities
            isAndroid = (/android/gi).test(navigator.appVersion)
            , isIDevice = (/iphone|ipad/gi).test(navigator.appVersion)
            , isPlaybook = (/playbook/gi).test(navigator.appVersion)
            , isTouchPad = (/hp-tablet/gi).test(navigator.appVersion)
            ,
            has3d = 'WebKitCSSMatrix'in window && 'm11'in new WebKitCSSMatrix()
            , hasTouch = 'ontouchstart'in window && !isTouchPad
            , hasTransform = vendor + 'Transform'in document.documentElement.style
            , hasTransitionEnd = isIDevice || isPlaybook
            ,
            nextFrame = (function() {
                    return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame || function(callback) {
                            return setTimeout(callback, 17);
                        }
                }
            )()
            , cancelFrame = (function() {
                    return window.cancelRequestAnimationFrame || window.webkitCancelAnimationFrame || window.webkitCancelRequestAnimationFrame || window.mozCancelRequestAnimationFrame || window.oCancelRequestAnimationFrame || window.msCancelRequestAnimationFrame || clearTimeout
                }
            )()
            ,
            // Events
            RESIZE_EV = 'onorientationchange'in window ? 'orientationchange' : 'resize'
            , START_EV = hasTouch ? 'touchstart' : 'mousedown'
            , MOVE_EV = hasTouch ? 'touchmove' : 'mousemove'
            , END_EV = hasTouch ? 'touchend' : 'mouseup'
            , CANCEL_EV = hasTouch ? 'touchcancel' : 'mouseup'
            ,
            // Helpers
            trnOpen = 'translate' + (has3d ? '3d(' : '(')
            , trnClose = has3d ? ',0)' : ')'
            ,
            // Constructor
            iScroll = function(el, options) {
                var that = this, doc = document, i;

                that.wrapper = typeof el == 'object' ? el : doc.getElementById(el);
                that.wrapper.style.overflow = 'hidden';
                that.scroller = that.wrapper.children[0];

                // Default options
                that.options = {
                    hScroll: true,
                    vScroll: true,
                    x: 0,
                    y: 0,
                    bounce: true,
                    bounceLock: false,
                    momentum: true,
                    lockDirection: true,
                    useTransform: true,
                    useTransition: false,

                    // Events
                    onRefresh: null,
                    onBeforeScrollStart: function(e) {
                        e.preventDefault();
                    },
                    onScrollStart: null,
                    onBeforeScrollMove: null,
                    onScrollMove: null,
                    onBeforeScrollEnd: null,
                    onScrollEnd: null,
                    onTouchEnd: null,
                    onDestroy: null
                };

                // User defined options
                for (i in options)
                    that.options[i] = options[i];

                // Set starting position
                that.x = that.options.x;
                that.y = that.options.y;

                // Normalize options
                that.options.useTransform = hasTransform ? that.options.useTransform : false;
                that.options.hScrollbar = that.options.hScroll && that.options.hScrollbar;
                that.options.vScrollbar = that.options.vScroll && that.options.vScrollbar;
                that.options.useTransition = hasTransitionEnd && that.options.useTransition;

                // Set some default styles
                that.scroller.style[vendor + 'TransitionProperty'] = that.options.useTransform ? '-' + vendor.toLowerCase() + '-transform' : 'top left';
                that.scroller.style[vendor + 'TransitionDuration'] = '0';
                that.scroller.style[vendor + 'TransformOrigin'] = '0 0';
                if (that.options.useTransition)
                    that.scroller.style[vendor + 'TransitionTimingFunction'] = 'cubic-bezier(0.33,0.66,0.66,1)';

                if (that.options.useTransform)
                    that.scroller.style[vendor + 'Transform'] = trnOpen + that.x + 'px,' + that.y + 'px' + trnClose;
                else
                    that.scroller.style.cssText += ';position:absolute;top:' + that.y + 'px;left:' + that.x + 'px';

                that.refresh();

                that._bind(RESIZE_EV, window);
                that._bind(START_EV);
                if (!hasTouch)
                    that._bind('mouseout', that.wrapper);
            };

        // Prototype
        iScroll.prototype = {
            enabled: true,
            x: 0,
            y: 0,
            steps: [],
            scale: 1,

            handleEvent: function(e) {
                var that = this;
                switch (e.type) {
                    case START_EV:
                        if (!hasTouch && e.button !== 0)
                            return;
                        that._start(e);
                        break;
                    case MOVE_EV:
                        that._move(e);
                        break;
                    case END_EV:
                    case CANCEL_EV:
                        that._end(e);
                        break;
                    case RESIZE_EV:
                        that._resize();
                        break;
                    case 'mouseout':
                        that._mouseout(e);
                        break;
                    case 'webkitTransitionEnd':
                        that._transitionEnd(e);
                        break;
                }
            },

            _resize: function() {
                this.refresh();
            },

            _pos: function(x, y) {
                x = this.hScroll ? x : 0;
                y = this.vScroll ? y : 0;

                if (this.options.useTransform) {
                    this.scroller.style[vendor + 'Transform'] = trnOpen + x + 'px,' + y + 'px' + trnClose + ' scale(' + this.scale + ')';
                } else {
                    x = mround(x);
                    y = mround(y);
                    this.scroller.style.left = x + 'px';
                    this.scroller.style.top = y + 'px';
                }

                this.x = x;
                this.y = y;
            },

            _start: function(e) {
                var that = this, point = hasTouch ? e.touches[0] : e, matrix, x, y;

                if (!that.enabled)
                    return;

                if (that.options.onBeforeScrollStart)
                    that.options.onBeforeScrollStart.call(that, e);

                if (that.options.useTransition)
                    that._transitionTime(0);

                that.moved = false;
                that.animating = false;
                that.zoomed = false;
                that.distX = 0;
                that.distY = 0;
                that.absDistX = 0;
                that.absDistY = 0;
                that.dirX = 0;
                that.dirY = 0;

                if (that.options.momentum) {
                    if (that.options.useTransform) {
                        // Very lame general purpose alternative to CSSMatrix
                        matrix = getComputedStyle(that.scroller, null)[vendor + 'Transform'].replace(/[^0-9-.,]/g, '').split(',');
                        x = matrix[4] * 1;
                        y = matrix[5] * 1;
                    } else {
                        x = getComputedStyle(that.scroller, null).left.replace(/[^0-9-]/g, '') * 1;
                        y = getComputedStyle(that.scroller, null).top.replace(/[^0-9-]/g, '') * 1;
                    }

                    if (x != that.x || y != that.y) {
                        if (that.options.useTransition)
                            that._unbind('webkitTransitionEnd');
                        else
                            cancelFrame(that.aniTime);
                        that.steps = [];
                        that._pos(x, y);
                    }
                }

                that.startX = that.x;
                that.startY = that.y;
                that.pointX = point.pageX;
                that.pointY = point.pageY;

                that.startTime = e.timeStamp || Date.now();

                if (that.options.onScrollStart)
                    that.options.onScrollStart.call(that, e);

                that._bind(MOVE_EV);
                that._bind(END_EV);
                that._bind(CANCEL_EV);
            },

            _move: function(e) {
                var that = this
                    , point = hasTouch ? e.touches[0] : e
                    , deltaX = point.pageX - that.pointX
                    , deltaY = point.pageY - that.pointY
                    , newX = that.x + deltaX
                    , newY = that.y + deltaY
                    , timestamp = e.timeStamp || Date.now();

                if (that.options.onBeforeScrollMove)
                    that.options.onBeforeScrollMove.call(that, e);

                that.pointX = point.pageX;
                that.pointY = point.pageY;

                // Slow down if outside of the boundaries
                if (newX > 0 || newX < that.maxScrollX) {
                    newX = that.options.bounce ? that.x + (deltaX / 2) : newX >= 0 || that.maxScrollX >= 0 ? 0 : that.maxScrollX;
                }
                if (newY > 0 || newY < that.maxScrollY) {
                    newY = that.options.bounce ? that.y + (deltaY / 2) : newY >= 0 || that.maxScrollY >= 0 ? 0 : that.maxScrollY;
                }

                that.distX += deltaX;
                that.distY += deltaY;
                that.absDistX = m.abs(that.distX);
                that.absDistY = m.abs(that.distY);

                if (that.absDistX < 6 && that.absDistY < 6) {
                    return;
                }

                // Lock direction
                if (that.options.lockDirection) {
                    if (that.absDistX > that.absDistY + 5) {
                        newY = that.y;
                        deltaY = 0;
                    } else if (that.absDistY > that.absDistX + 5) {
                        newX = that.x;
                        deltaX = 0;
                    }
                }

                that.moved = true;
                that._pos(newX, newY);
                that.dirX = deltaX > 0 ? -1 : deltaX < 0 ? 1 : 0;
                that.dirY = deltaY > 0 ? -1 : deltaY < 0 ? 1 : 0;

                if (timestamp - that.startTime > 300) {
                    that.startTime = timestamp;
                    that.startX = that.x;
                    that.startY = that.y;
                }

                if (that.options.onScrollMove)
                    that.options.onScrollMove.call(that, e);
            },

            _end: function(e) {
                if (hasTouch && e.touches.length != 0)
                    return;

                var that = this, point = hasTouch ? e.changedTouches[0] : e, target, ev, momentumX = {
                    dist: 0,
                    time: 0
                }, momentumY = {
                    dist: 0,
                    time: 0
                }, duration = (e.timeStamp || Date.now()) - that.startTime, newPosX = that.x, newPosY = that.y, newDuration;

                that._unbind(MOVE_EV);
                that._unbind(END_EV);
                that._unbind(CANCEL_EV);

                if (that.options.onBeforeScrollEnd)
                    that.options.onBeforeScrollEnd.call(that, e);

                if (!that.moved) {
                    if (hasTouch) {
                        // Find the last touched element
                        target = point.target;
                        while (target.nodeType != 1)
                            target = target.parentNode;

                        if (target.tagName != 'SELECT' && target.tagName != 'INPUT' && target.tagName != 'TEXTAREA') {
                            ev = document.createEvent('MouseEvents');
                            ev.initMouseEvent('click', true, true, e.view, 1, point.screenX, point.screenY, point.clientX, point.clientY, e.ctrlKey, e.altKey, e.shiftKey, e.metaKey, 0, null);
                            ev._fake = true;
                            target.dispatchEvent(ev);
                        }
                    }

                    that._resetPos(200);

                    if (that.options.onTouchEnd)
                        that.options.onTouchEnd.call(that, e);
                    return;
                }

                if (duration < 300 && that.options.momentum) {
                    momentumX = newPosX ? that._momentum(newPosX - that.startX, duration, -that.x, that.scrollerW - that.wrapperW + that.x, that.options.bounce ? that.wrapperW : 0) : momentumX;
                    momentumY = newPosY ? that._momentum(newPosY - that.startY, duration, -that.y, (that.maxScrollY < 0 ? that.scrollerH - that.wrapperH + that.y : 0), that.options.bounce ? that.wrapperH : 0) : momentumY;

                    newPosX = that.x + momentumX.dist;
                    newPosY = that.y + momentumY.dist;

                    if ((that.x > 0 && newPosX > 0) || (that.x < that.maxScrollX && newPosX < that.maxScrollX))
                        momentumX = {
                            dist: 0,
                            time: 0
                        };
                    if ((that.y > 0 && newPosY > 0) || (that.y < that.maxScrollY && newPosY < that.maxScrollY))
                        momentumY = {
                            dist: 0,
                            time: 0
                        };
                }

                if (momentumX.dist || momentumY.dist) {
                    newDuration = m.max(m.max(momentumX.time, momentumY.time), 10);

                    that.scrollTo(mround(newPosX), mround(newPosY), newDuration);

                    if (that.options.onTouchEnd)
                        that.options.onTouchEnd.call(that, e);
                    return;
                }

                that._resetPos(200);
                if (that.options.onTouchEnd)
                    that.options.onTouchEnd.call(that, e);
            },

            _resetPos: function(time) {
                var that = this
                    , resetX = that.x >= 0 ? 0 : that.x < that.maxScrollX ? that.maxScrollX : that.x
                    , resetY = that.y >= 0 || that.maxScrollY > 0 ? 0 : that.y < that.maxScrollY ? that.maxScrollY : that.y;

                if (resetX == that.x && resetY == that.y) {
                    if (that.moved) {
                        if (that.options.onScrollEnd)
                            that.options.onScrollEnd.call(that);
                        // Execute custom code on scroll end
                        that.moved = false;
                    }

                    return;
                }

                that.scrollTo(resetX, resetY, time || 0);
            },

            _mouseout: function(e) {
                var t = e.relatedTarget;

                if (!t) {
                    this._end(e);
                    return;
                }

                while (t = t.parentNode)
                    if (t == this.wrapper)
                        return;

                this._end(e);
            },

            _transitionEnd: function(e) {
                var that = this;

                if (e.target != that.scroller)
                    return;

                that._unbind('webkitTransitionEnd');

                that._startAni();
            },

            /**
             *
             * Utilities
             *
             */
            _startAni: function() {
                var that = this, startX = that.x, startY = that.y, startTime = Date.now(), step, easeOut, animate;

                if (that.animating)
                    return;

                if (!that.steps.length) {
                    that._resetPos(400);
                    return;
                }

                step = that.steps.shift();

                if (step.x == startX && step.y == startY)
                    step.time = 0;

                that.animating = true;
                that.moved = true;

                if (that.options.useTransition) {
                    that._transitionTime(step.time);
                    that._pos(step.x, step.y);
                    that.animating = false;
                    if (step.time)
                        that._bind('webkitTransitionEnd');
                    else
                        that._resetPos(0);
                    return;
                }

                animate = function() {
                    var now = Date.now(), newX, newY;

                    if (now >= startTime + step.time) {
                        that._pos(step.x, step.y);
                        that.animating = false;
                        if (that.options.onAnimationEnd)
                            that.options.onAnimationEnd.call(that);
                        // Execute custom code on animation end
                        that._startAni();
                        return;
                    }

                    now = (now - startTime) / step.time - 1;
                    easeOut = m.sqrt(1 - now * now);
                    newX = (step.x - startX) * easeOut + startX;
                    newY = (step.y - startY) * easeOut + startY;
                    that._pos(newX, newY);
                    if (that.animating)
                        that.aniTime = nextFrame(animate);
                }
                ;

                animate();
            },

            _transitionTime: function(time) {
                this.scroller.style[vendor + 'TransitionDuration'] = time + 'ms';
            },

            _momentum: function(dist, time, maxDistUpper, maxDistLower, size) {
                var deceleration = 0.0006
                    , speed = m.abs(dist) / time
                    , newDist = (speed * speed) / (2 * deceleration)
                    , newTime = 0
                    , outsideDist = 0;

                // Proportinally reduce speed if we are outside of the boundaries
                if (dist > 0 && newDist > maxDistUpper) {
                    outsideDist = size / (6 / (newDist / speed * deceleration));
                    maxDistUpper = maxDistUpper + outsideDist;
                    speed = speed * maxDistUpper / newDist;
                    newDist = maxDistUpper;
                } else if (dist < 0 && newDist > maxDistLower) {
                    outsideDist = size / (6 / (newDist / speed * deceleration));
                    maxDistLower = maxDistLower + outsideDist;
                    speed = speed * maxDistLower / newDist;
                    newDist = maxDistLower;
                }

                newDist = newDist * (dist < 0 ? -1 : 1);
                newTime = speed / deceleration;

                return {
                    dist: newDist,
                    time: mround(newTime)
                };
            },

            _offset: function(el) {
                var left = -el.offsetLeft
                    , top = -el.offsetTop;

                while (el = el.offsetParent) {
                    left -= el.offsetLeft;
                    top -= el.offsetTop;
                }

                return {
                    left: left,
                    top: top
                };
            },

            _bind: function(type, el, bubble) {
                (el || this.scroller).addEventListener(type, this, !!bubble);
            },

            _unbind: function(type, el, bubble) {
                (el || this.scroller).removeEventListener(type, this, !!bubble);
            },

            /**
             *
             * Public methods
             *
             */
            destroy: function() {
                var that = this;

                that.scroller.style[vendor + 'Transform'] = '';

                // Remove the event listeners
                that._unbind(RESIZE_EV, window);
                that._unbind(START_EV);
                that._unbind(MOVE_EV);
                that._unbind(END_EV);
                that._unbind(CANCEL_EV);
                that._unbind('mouseout', that.wrapper);
                if (that.options.useTransition)
                    that._unbind('webkitTransitionEnd');

                if (that.options.onDestroy)
                    that.options.onDestroy.call(that);
            },

            refresh: function() {
                var that = this, offset;

                that.wrapperW = that.wrapper.clientWidth;
                that.wrapperH = that.wrapper.clientHeight;

                that.scrollerW = that.scroller.offsetWidth;
                that.scrollerH = that.scroller.offsetHeight;
                that.maxScrollX = that.wrapperW - that.scrollerW;
                that.maxScrollY = that.wrapperH - that.scrollerH;
                that.dirX = 0;
                that.dirY = 0;

                that.hScroll = that.options.hScroll && that.maxScrollX < 0;
                that.vScroll = that.options.vScroll && (!that.options.bounceLock && !that.hScroll || that.scrollerH > that.wrapperH);

                offset = that._offset(that.wrapper);
                that.wrapperOffsetLeft = -offset.left;
                that.wrapperOffsetTop = -offset.top;

                that.scroller.style[vendor + 'TransitionDuration'] = '0';

                that._resetPos(200);
            },

            scrollTo: function(x, y, time, relative) {
                var that = this, step = x, i, l;

                that.stop();

                if (!step.length)
                    step = [{
                        x: x,
                        y: y,
                        time: time,
                        relative: relative
                    }];

                for (i = 0,
                         l = step.length; i < l; i++) {
                    if (step[i].relative) {
                        step[i].x = that.x - step[i].x;
                        step[i].y = that.y - step[i].y;
                    }
                    that.steps.push({
                        x: step[i].x,
                        y: step[i].y,
                        time: step[i].time || 0
                    });
                }

                that._startAni();
            },

            scrollToElement: function(el, time) {
                var that = this, pos;
                el = el.nodeType ? el : that.scroller.querySelector(el);
                if (!el)
                    return;

                pos = that._offset(el);
                pos.left += that.wrapperOffsetLeft;
                pos.top += that.wrapperOffsetTop;

                pos.left = pos.left > 0 ? 0 : pos.left < that.maxScrollX ? that.maxScrollX : pos.left;
                pos.top = pos.top > 0 ? 0 : pos.top < that.maxScrollY ? that.maxScrollY : pos.top;
                time = time === undefined ? m.max(m.abs(pos.left) * 2, m.abs(pos.top) * 2) : time;

                that.scrollTo(pos.left, pos.top, time);
            },

            disable: function() {
                this.stop();
                this._resetPos(0);
                this.enabled = false;

                // If disabled after touchstart we make sure that there are no left over events
                this._unbind(MOVE_EV);
                this._unbind(END_EV);
                this._unbind(CANCEL_EV);
            },

            enable: function() {
                this.enabled = true;
            },

            stop: function() {
                cancelFrame(this.aniTime);
                this.steps = [];
                this.moved = false;
                this.animating = false;
            }
        };

        if (typeof exports !== 'undefined')
            exports.iScroll = iScroll;
        else
            window.iScroll = iScroll;

    }
)();
